jxl导入，导出

pom.xml引入包：
    <dependency>
        <groupId>net.sourceforge.jexcelapi</groupId>
        <artifactId>jxl</artifactId>
        <version>2.6.12</version>
    </dependency>

代码：
/**
	 * 导入Excel数据

	 */
    @PostMapping("import")
	public AjaxResult importTradLine(@RequestParam(value = "file", required = false)MultipartFile file,@RequestParam String userId){
    	
    	int b=0;
    	Date date = new Date();
		DateFormat df = new SimpleDateFormat("hh:mm:ss");
		SimpleDateFormat dfs = new SimpleDateFormat("yyyy-MM-dd hh:mm:ss");
		
		try {
			// 1.获取用户上传的文件
			Workbook workbook = Workbook.getWorkbook(file.getInputStream());
			
			if (workbook == null) {
				return error("导入Excel为空");
			}
			
			// 2.获取工作簿sheet
			Sheet sheet = workbook.getSheet(0);
			// 3.获取总行数
			int rows = sheet.getRows();
			System.out.println("rows:" + rows);
			for (int i = 1; i < rows; i++) {
//			Students students = new Students();
				//Cell oCell= oFirstSheet.getCell(j,i);//需要注意的是这里的getCell方法的参数，第一个是指定第几列，第二个参数才是指定第几行  
				TradeLine tradeLine= new TradeLine();
				String company2 = sheet.getCell(1, i).getContents();
				String c1 =company2.replaceAll("\\s", "");
				String c2 =company.replaceAll("\\s", "");
				if (!c1.equals(c2)) {
					continue;
				}
				tradeLine.setSupplier(c1);
				tradeLine.setUnloadCompany(sheet.getCell(2, i).getContents());
				tradeLine.setGoods(sheet.getCell(3, i).getContents());
				tradeLine.setCarNumber(sheet.getCell(4, i).getContents());
				tradeLine.setUnloadNumber(sheet.getCell(5, i).getContents());
				tradeLine.setPrice(Double.parseDouble(sheet.getCell(6,i).getContents()));
				tradeLine.setTon(Double.parseDouble(sheet.getCell(7, i).getContents()));
			  tradeLine.setAmounts(Double.parseDouble(sheet.getCell(8,i).getContents()));
				
				String unloadTime=sheet.getCell(9, i).getContents();
				String begin = unloadTime + " " + df.format(date);
				Date d = dfs.parse(begin);
				tradeLine.setUnloadDate(d);
				tradeLine.setCreateDate(new Date());
				// 4.添加到数据库中
				int a =tradeLineService.insert(tradeLine);
				b++;
			}
			// 5.关闭资源
			workbook.close();
		} catch (Exception e) {
			e.printStackTrace();
		} 
		System.out.println("共导入了" + b + "条");
		return success("共成功执行了" + b + "条");
	}

	
	/**
	 * 下载导入数据模板
	 */
    @GetMapping("import/template")
    public AjaxResult exportTemplate(HttpServletRequest request,HttpServletResponse response) throws Exception {
        // 1.文件下载响应头
        response.setContentType("application/msexcel");
        response.addHeader("Content-Disposition", "attachment; filename=" + URLEncoder.encode("模板导出.xls", "UTF-8"));
        response.setCharacterEncoding("utf-8");
        // 2.响应到浏览器
        WritableWorkbook workbook = Workbook.createWorkbook(response.getOutputStream());
        
        /**
		 * 定义单元格样式
		 */
		WritableFont wf_title = new WritableFont(WritableFont.ARIAL, 12,
				WritableFont.BOLD, false, UnderlineStyle.NO_UNDERLINE,
				jxl.format.Colour.RED); // 定义格式 字体 下划线 斜体 粗体 颜色
		WritableFont wf_head = new WritableFont(WritableFont.ARIAL, 12,
				WritableFont.BOLD, false, UnderlineStyle.NO_UNDERLINE,
				jxl.format.Colour.BLACK); // 定义格式 字体 下划线 斜体 粗体 颜色
		WritableFont wf_table = new WritableFont(WritableFont.ARIAL, 8,
				WritableFont.BOLD, false, UnderlineStyle.NO_UNDERLINE,
				jxl.format.Colour.BLACK); // 定义格式 字体 下划线 斜体 粗体 颜色
	
		WritableCellFormat wcf_title = new WritableCellFormat(wf_title); // 单元格定义
		wcf_title.setBackground(jxl.format.Colour.BLACK); // 设置单元格的背景颜色
		wcf_title.setAlignment(jxl.format.Alignment.CENTRE); // 设置对齐方式
	
		WritableCellFormat wcf_head = new WritableCellFormat(wf_head); 
		wcf_head.setBackground(jxl.format.Colour.BLACK);
		wcf_head.setAlignment(jxl.format.Alignment.CENTRE); 
	
		WritableCellFormat wcf_table = new WritableCellFormat(wf_table); 
		wcf_table.setBackground(jxl.format.Colour.BLACK); 
		wcf_table.setAlignment(jxl.format.Alignment.CENTRE); 
        
        
        // 创建工作簿sheet
        WritableSheet sheet = workbook.createSheet("模板", 0);
        // 3.设置column名
        sheet.addCell(new Label(0, 0, "序号",wcf_head));
        sheet.addCell(new Label(1, 0, "供应单位",wcf_head));
        sheet.addCell(new Label(2, 0, "卸货厂家",wcf_head));
        sheet.addCell(new Label(3, 0, "货品种类",wcf_head));
        sheet.addCell(new Label(4, 0, "车牌号码",wcf_head));
        sheet.addCell(new Label(5, 0, "卸货磅单",wcf_head));
        sheet.addCell(new Label(6, 0, "货品单价(元/吨)",wcf_head));
        sheet.addCell(new Label(7, 0, "卸货吨数",wcf_head));
        sheet.addCell(new Label(8, 0, "总金额(元)",wcf_head));
        sheet.addCell(new Label(9, 0, "卸货日期",wcf_head));

        // 4.把核保的数据填充到工作簿中 service调用selectExport()查询数据库
        System.out.println("开始导出...");
        long s1 = System.currentTimeMillis();
       
        // 5.写入数据
        workbook.write();
        // 6.关闭资源
        workbook.close();

        long s2 = System.currentTimeMillis();
        long time = s2 - s1;
        System.out.println("导出完成！消耗时间：" + time + "毫秒");
        return null;
    }

 备注：如果是查询数据库数据，导出数据，在导出模板代码块中，加入个循环插入即可，不再重复写代码了。